1. Field of the Invention
The present invention relates to a material for processing usable for, for example, a target which generates vibration or noise and formed of a single thin plate performing a vibration damping function or a sound absorption function on the target, and a molded member using the same.
2. Background Art
One example of such a target which generates vibration is an internal combustion engine. From a main body of an internal combustion engine or an exhaust system connected to the internal combustion engine such as an exhaust manifold or the like, heat, noise, vibration or the like is released outside. In order to prevent an unnecessary release of vibration from a vibration source such the internal combustion engine main body, the exhaust system or the like to the outside, various types of covers such as an insulator are used for the vibration source.
FIG. 18 is an isometric view of a typical conventional exhaust manifold insulator 1 (hereinafter, referred to as the “insulator”) described in Japanese Laid-Open Patent Publication No. 10-266850 (e.g., paragraph 8 through 11, and FIG. 1 of the reference) mentioned below. Hereinafter, the insulator 1 will be described with reference to FIG. 18.
The insulator 1 is attached to, and covers, an exhaust manifold of an internal combustion engine. The insulator 1 includes a substantially flat front part 1a and a side part 1b bent from the front part 1a and extending toward a cylinder head of the internal combustion engine. The insulator 1 is formed of an assembly of two steel plates 1A and 1B brought together, and one of the two steel plates is folded onto the other steel plate along a folding line at least one appropriate position on an edge of each slit 2. This folding arrangement reinforces the bonding of the two steel plates 1A and 1B.
Due to the structure in which the two steel plates 1A and 1B are brought together, the conventional insulator 1 acts such that the vibration at a frequency of several thousand cycles per minute generated from the exhaust manifold, in which high temperature exhaust gas pulsating at such a frequency passes, is not unnecessarily released to an outside environment.
Such a conventional insulator has a structure in which two steel plates 1A and 1B are brought together as described above, and has a problem of being relatively heavy. There is another problem that the insulator 1 causes plane vibration due to vibration propagated from the exhaust manifold, and when the vibration frequency matches the resonance frequency of the insulator 1, the insulator 1 itself becomes a source of noise.